Search PubMed⌕ Search

Biomedical subjects

V Prakash

Publications and source records attributed to V Prakash.

At least 109 records · Page 6Linked to original sources
PubMed1983

The interaction of vincristine with calf brain tubulin.

The interaction of the antimitotic drug vincristine with tubulin has been investigated by the techniques of self-assembly, velocity sedimentation, fluorescence, circular dichroism, and differential spectroscopy. Vincristine has been shown to inhibit the self-assembly of tubulin into microtubules at substoichiometric concentrations. The sedimentation velocity patterns at low vincristine concentration (less than 1 X 10(-5) M to 7 X 10(-5) M) consist of a bimodal boundary with a 5.8 S peak and a fast moving peak, with a nominal S20,w value of 9 S. The data conform to the ligand-promoted self-association theory of Cann and Goad (Cann, J.R., and Goad, W.B. (1972) Arch. Biochem. Biophys. 153, 603-609). At higher vincristine concentrations (greater than 8 X 10(-5 M), most of the protein is polymerized and sediments as a hypersharp peak with a nominal S20,w value of approximately 20 S. The association constant for the binding of vincristine to tubulin, determined by spectrofluorometry, is 3.5 X 10(4) liters/mol at 25 degrees C. The binding of vincristine does not induce any significant conformational changes in tubulin; however, the difference spectral results indicate perturbation of both vincristine and protein chromophores.

Animals↗
PubMed1983

The resolution of bimodal peaks in the analytical ultracentrifuge in the presence and absence of ligands.

The patterns for peak resolution in the analytical ultracentrifuge characteristic of systems associating by different mechanisms are analyzed. These are (i) that in which reequilibration is infinitely slow; (ii) that in which reequilibration is rapid, i.e., a Gilbert-type system; and (iii) that in which reequilibration is rapid, but the self-association is mediated by a ligand. Criteria for distinguishing the three are described and illustrated by results on tubulin self-association under various conditions.

Buffers↗
PubMed1983

Radionuclide assessment of heterotopic ossification in spinal cord injury patients.

Whole body 99Tc-pyrophosphate bone scans were obtained and correlated with skeletal radiographs for detection of heterotopic ossification in 135 spinal injury patients. There were 40 patients with recent injury (less than 6 months) and 95 with injury of over 6 months duration. Heterotopic new bone was detected on the bone scan in 33.7% of 95 patients with spinal cord injuries of more than 6 months duration and 30% of 40 patients with injuries of less than 6 months. The radionuclide scan was found to be useful in detection of heterotopic ossification at its early stage and in its differentiation from other complications in spinal cord injury patients.

Adult↗
PubMed1983

Low serum 3,3',5-triiodothyronine (T3) and reciprocally high serum 3,3',5'-triiodothyronine (reverse T3) concentration in spinal cord injury patients.

Thyroid function tests were performed on 115 spinal cord injury patients. Serum thyroxine, thyroid stimulating hormone, and T3 resin uptake were within normal range in all patients. Serum T3 levels tended to be low in paraplegic and quadriplegic patients, even though they were clinically euthyroid and other thyroid functions were normal. Serum reverse T3 levels were reciprocally higher in these patients.

Adolescent↗
PubMed1980

Thyroid hypofunction in spinal cord injury patients.

Our experience in the screening and detection of hypothyroidism in 225 spinal injury patients is described. Clinical features compatible with hypothyroidism are frequently encountered in these patients and require thyroid function testing to exclude or confirm thyroid hypofunction. Two cases of hypothyroidism, equivocal on clinical grounds alone, were first detected by a low value in screening tests for serum thyroxine levels and subsequently confirmed by a high serum TSH level. Low serum triiodiothyronine level is frequently found in apparently euthyroid patients with tetraplegia and is necessarily not an indicator of clinical hypothyroidism in these patients.

Adolescent↗
PubMed1980

Effect of sodium dodecyl sulfate, acid, alkali, urea and guanidine hydrochloride on the circular dichroism of alpha-globulin of Sesamum indicum L.

The circular dichrotic spectra of alpha-globulin have been obtained under various solution conditions of sodium dodecyl sulfate, acid, alkali, urea and guanidine hydrochloride. The protein in phosphate buffer pH 7.4, 0.2 M has about 25% beta-structure and 5% alpha-helix, the rest being aperiodic or irregular structure. Sodium dodecyl sulfate induced more alpha-helical structure in the protein. The protein had nearly 20% alpha-helix at 1 X 10(-2) M SDS. At extreme acid or alkaline pH, the protein had no alpha-helix with beta-structure decreasing with further extremes of pH. The protein is represented by 100% aperiodic structure in 6.6 M urea and in 6.0 M guanidine hydrochloride solutions. The above results are discussed in view of some of the earlier results with regard to the association-dissociation and denaturation behavior of alpha-globulin under various solution conditions.

Acids↗
PubMed1979

beta-thromboglobulin in antecubital vein blood--the influence of age, sex and blood group.

Samples of blood for estimation of beta-thromboglobulin (B.T.G.) in normal subjects have been obtained both from blood donors at the end of their donation and from other volunteers by standard venepuncture. The former was a satisfactory method in males only. By standard venepuncture females have on average lower values than males and in the pre-menopausal age groups the difference is statistically significant. Mean values vary little up to 59 years after which they rise slowly but steadily. There is no significant difference in the mean B.T.G. values between the ABO blood groups.

ABO Blood-Group System↗